BestSQLquery

CREATE database FAQ

create table Students(id int,name varchar(100),marks int)

insert into Students select 1,'aa',60

insert into Students select 2,'bb',70

insert into Students select 3,'cc',80

insert into Students select 4,'dd',50

insert into Students select 5,'ee',80

alter table Students add  grade varchar(5)

--question: we have table students with id,name,marks so i want to include a column Grade,which is fill or update that column?

-- based on marks grade will be updated in one shot.

update Students set Grade=(

 case 

 when marks>60 then 'A' 

 when marks<50 then 'B'

 else

 'C'

 end)

 Results

 Select * from Students

id name marks grade

1 aa 60 C

2 bb 70 A

3 cc 80 A

4 dd 50 C

5 ee 80 A

--query2: based on marks,give me second rank count.

select * from Students

--1ST RANK count

with result as

(

select id,marks,dense_rank() over(order by marks desc) as dens from Students

)select count(*) from result where dens=1

select id,marks,dense_rank() over(order by marks) as dens from Students

---------------------------Results------------------

id marks dens

4 50 1

1 60 2

2 70 3

3 80 4

5 80 4

select id,marks,dense_rank() over(order by marks desc) as dens from Students

id marks dens

3 80 1

5 80 1

2 70 2

1 60 3

4 50 4

--2nd rank count

with result

(

select id,marks,dense_rank() over(order by marks desc)as dens from Students

)select count(*) from result where dens=1

CREATE TABLE T2(ID INT, NAME VARCHAR(10))

TRUNCATE TABLE T2

INSERT INTO T2 VALUES (1,'A')

INSERT INTO T2 VALUES (1,'A')

INSERT INTO T2 VALUES (2,'B')

INSERT INTO T2 VALUES (2,'C')

INSERT INTO T2 VALUES (3,'D')

INSERT INTO T2 VALUES (4,'D')

INSERT INTO T2 VALUES (5,'E')

INSERT INTO T2 VALUES (6,'F')

INSERT INTO T2 VALUES (6,'G')

CREATE FUNCTION [DBO].ConcatValues (@METHOD VARCHAR(20))

RETURNS VARCHAR(1000)

AS

BEGIN

DECLARE @OUTPUT VARCHAR(1000)

DECLARE @TBL TABLE(ID INT,NAME VARCHAR(20))

INSERT INTO @TBL SELECT DISTINCT ID,NAME FROM T2 WHERE ID = @METHOD

SELECT @OUTPUT = COALESCE(@OUTPUT + ',' , '') + NAME FROM @TBL

WHERE ID = @METHOD

ORDER BY ID

RETURN @OUTPUT

END

select * from  T2

SELECT  ID, [DBO].CONCATVALUES(ID) FROM T2

create proc getchanges

(@mno int =null

)

as

if @mno is null

begin

raiserror('must be given',1,1)

return

end;

exec getchanges

--SQL SERVER – How to Retrieve TOP and BOTTOM Rows Together using T-SQL – Part 3

USE AdventureWorks

GO

SELECT A.*

FROM

(

SELECT TOP 1 *

FROM Sales.SalesOrderDetail

ORDER BY SalesOrderDetailID) A

UNION ALL

SELECT B.*

FROM

(

SELECT TOP 1 *

FROM Sales.SalesOrderDetail

ORDER BY SalesOrderDetailID DESC) B

GO

--another model

with TopBottomRow as

(

SELECT TOP 1 *

FROM Sales.SalesOrderDetail

ORDER BY SalesOrderDetailID

union all  ---useful note

SELECT TOP 1 *

FROM Sales.SalesOrderDetail

ORDER BY SalesOrderDetailID desc

)select * from TopBottomRow

========================================================

create table t1(id int)

create table t2(id int)

insert into t1 values(1)

insert into t1 values(1)

insert into t1 values(1)

insert into t2 values(1)

insert into t2 values(1)

insert into t2 values(1)

create table t3(id int,id2 int)

insert into t3 select 1,10

insert into t3 select 1,20

insert into t3 select 1,30

insert into t3 select 2,40

insert into t3 select 2,50

insert into t3 select 2,60

select * from t3

select id,max(id2) from t3 group by id

-------------

create table data2(id int,name varchar(250),login int,swipevarchar(50))

insert into data2 select 123,'aa',11,'in'

insert into data2 select 123,'bb',12,'in'

insert into data2 select 124,'aa',12,'out'

insert into data2 select 124,'aa',13,'out'

insert into data2 select 123,'aa',14,'in'

insert into data2 select 124,'aa',15,'in'

select id,max(login) from data2 group by id

create table data3(id int)

insert into data3 select 1000

insert into data3 select 2000

insert into data3 select 3000

insert into data3 select 4000

insert into data3 select 5000

insert into data3 select 6000

select * from data3

select MAX(id) from data3 where id<(select MAX(id) fromdata3)

select top 1 id from data3 where id=(select top 5 id fromdata3)

with result as

(

select id ,DENSE_RANK() over(order by id desc)as dens fromdata3

)

select top 1 id from result where dens=6

--query2

with result as

(

select id,DENSE_RANK()over(order by id desc) as dens fromdata3

)select top 1 id from result where dens=3

--query3

with resultposition as

(

select id,ROW_NUMBER()over(order by id )as rowposition fromdata3

)select id from resultposition where rowposition=3

create table data4(id int,id2 int)

insert into data4 select 1,10

insert into data4 select 1,20

insert into data4 select 1,30

insert into data4 select 2,10

insert into data4 select 2,20

insert into data4 select 2,90

insert into data4 select 3,100

insert into data4 select 3,120

select id,SUM(id2) from data4 group by id

select id,id2,sum(id2)over(partition by id )as rowpart fromdata4

create table data5(sal int)

insert into data5 select 1000

insert into data5 select 2000

insert into data5 select 1000

insert into data5 select 3000

insert into data5 select 3000

select * from data5

with resultdup as

(

select sal, ROW_NUMBER() over(partition by sal order bysal)as rowdup from data5

)select sal,rowdup from resultdup where rowdup>1 --Here need to write delete code

select distinct sal,count(*) from data5 group by sal havingCOUNT(*)>1

=======================================================

Scope_Identity()

================

                Returns the last identity inserted in the current scope and session (It is not affected by other connections or tables

nor by triggers)

@@Identity

==========

                Will return the last identify value inserted in any scope. (This means that adding replication or auditing triggers to

a database can alter the value of @@Identity)

Ident_Current('Stud')

=====================

                Returns the last value inserted in to that table on any connection

Note:

=====

                As stated earlier scope_identity() is probably the only one of the functions that you will need to use

                Only one identity column per table

                For existing column we cannot add identity column, or drop the existing one , But we can add new column with Identity

ALTER TABLE RawData

  ADD Balance INT

ALTER TABLE RawData

  ADD ID INT IDENTITY NOT NULL PRIMARY KEY

Go

-- You can also specify the Primary key as Non Clustered

CREATE TABLE Fable

(

FableID INT                         NOT NULL CONSTRAINT FablePK PRIMARY KEY NONCLUSTERED,

  Title     ntext                     NOT NULL,

  Moral text                        NOT NULL,

FableText            VARCHAR(1536)               NOT NULL

)

go

Just Some Ex's for adding constraints in different ways

-------------------------------------------------------

CREATE DATABASE ProtectionChapter

go

USE ProtectionChapter

Go

------------------------------------------------------------------------------------------------------

-- Automatic Data Protection - Declarative Data Protection

------------------------------------------------------------------------------------------------------

CREATE SCHEMA Music

GO

CREATE TABLE Music.Artist

(

ArtistIdint NOT NULL,

   Name varchar(60) NOT NULL,

   CONSTRAINT PKNameArtist PRIMARY KEY CLUSTERED (ArtistId),

   CONSTRAINT AKNameArtist_Name UNIQUE NONCLUSTERED (Name)

)

CREATE TABLE Music.Publisher

(

PublisherIdint primary key,

        Name                      varchar(20),

CatalogNumberMaskvarchar(100)

        CONSTRAINT DfltNamePublisher_CatalogNumberMask default ('%'),

        CONSTRAINT AKNamePublisher_Name UNIQUE NONCLUSTERED (Name),

)

CREATE TABLE Music.Album

(

AlbumIdint NOT NULL,

   Name varchar(60) NOT NULL,

ArtistIdint NOT NULL,

CatalogNumbervarchar(20) NOT NULL,

PublisherIdint NOT null --not requiring this information

   CONSTRAINT PKAlbum PRIMARY KEY CLUSTERED(AlbumId),

   CONSTRAINT AKAlbum_Name UNIQUE NONCLUSTERED (Name),

   CONSTRAINT FKMusic_Artist$records$Music_Album

            FOREIGN KEY (ArtistId) REFERENCES Music.Artist(ArtistId),

   CONSTRAINT FKMusic_Publisher$published$Music_Album

            FOREIGN KEY (PublisherId) REFERENCES Music.Publisher(PublisherId)

)

GO

INSERT  INTOMusic.Publisher (PublisherId, Name, CatalogNumberMask)

VALUES (1,'Capitol',

        '[0-9][0-9][0-9]-[0-9][0-9][0-9a-z][0-9a-z][0-9a-z]-[0-9][0-9]'),

        (2,'MCA', '[a-z][a-z][0-9][0-9][0-9][0-9][0-9]')

INSERT  INTOMusic.Artist(ArtistId, Name)

VALUES (1, 'The Beatles'),(2, 'The Who')

INSERT INTO Music.Album (AlbumId, Name, ArtistId, PublisherId, CatalogNumber)

VALUES (1, 'The White Album',1,1,'433-43ASD-33'),

       (2, 'Revolver',1,1,'111-11111-11'),

       (3, 'Quadrophenia',2,2,'CD12345')

GO

ALTER TABLE Music.Artist WITH CHECK

   ADD CONSTRAINT chkMusic_Artist$Name$NoDuranNames

           CHECK (Name not like '%Duran%')

GO

------------------------------------------------------------------------------------------------------

-- Automatic Data Protection - Declarative Data Protection - [WITH CHECK | WITH NOCHECK]

-----------------------------------------------------------------------------------------------------

INSERT INTO Music.Artist(ArtistId, Name)

VALUES (3, 'Duran Duran')

GO

INSERT INTO Music.Artist(ArtistId, Name)

VALUES (3, 'Madonna')

GO

ALTER TABLE Music.Artist WITH NOCHECK

   ADD CONSTRAINT chkMusic_Artist$Name$noMadonnaNames

           CHECK (Name not like '%Madonna%')

Go

UPDATE Music.Artist

SET Name = Name

GO

SELECT CHECK_CLAUSE,

objectproperty(object_id(CONSTRAINT_SCHEMA + '.' +

                                 CONSTRAINT_NAME),'CnstIsNotTrusted') AS NotTrusted

FROM INFORMATION_SCHEMA.CHECK_CONSTRAINTS

WHERE CONSTRAINT_SCHEMA = 'Music'

  And CONSTRAINT_NAME = 'chkMusic_Artist$Name$noMadonnaNames'

------------------------------------------------------------------------------------------------------

-- Automatic Data Protection - Declarative Data Protection - CHECK Constraints Based on Simple Expressions

------------------------------------------------------------------------------------------------------

INSERT INTO Music.Album( AlbumId, Name, ArtistId, PublisherId, CatalogNumber )

VALUES ( 4, '', 1, 1,'dummy value' )

GO

INSERT INTO Music.Album( AlbumId, Name, ArtistId, PublisherId, CatalogNumber )

VALUES ( 5, '', 1, 1,'dummy value' )

GO

DELETE FROM Music.Album

WHERE  Name = ''

GO

ALTER TABLE Music.Album WITH CHECK

   ADD CONSTRAINT chkMusic_Album$Name$noEmptyString

           CHECK (LEN(RTRIM(Name)) > 0)

#1

CREATE TABLE T1 (ID INT NOT NULL, SomeValCHAR(1));

ALTER TABLE T1 ADD CONSTRAINT [PK_ID] PRIMARY KEY CLUSTERED (ID);

CREATE TABLE T2 (FKID INT, SomeOtherValCHAR(2));

INSERT T1 (ID, SomeVal) SELECT 1, 'A';

INSERT T1 (ID, SomeVal) SELECT 2, 'B';

INSERT T2 (FKID, SomeOtherVal) SELECT 1, 'A1';

INSERT T2 (FKID, SomeOtherVal) SELECT 1, 'A2';

INSERT T2 (FKID, SomeOtherVal) SELECT 2, 'B1';

INSERT T2 (FKID, SomeOtherVal) SELECT 2, 'B2';

INSERT T2 (FKID, SomeOtherVal) SELECT 3, 'C1';  --orphan

INSERT T2 (FKID, SomeOtherVal) SELECT 3, 'C2';  --orphan

--Add the FK CONSTRAINT will fail because of existing orphaned records

ALTER TABLE T2 ADD CONSTRAINT FK_T2_T1 FOREIGN KEY (FKID) REFERENCES T1 (ID);   --fails

--Same as ADD above, but explicitly states the intent to CHECK the FK values before creating the CONSTRAINT

ALTER TABLE T2 WITH CHECK ADD CONSTRAINT FK_T2_T1 FOREIGN KEY (FKID) REFERENCES T1 (ID);    --fails

--Add the CONSTRAINT without checking existing values

ALTER TABLE T2 WITH NOCHECK ADD CONSTRAINT FK_T2_T1 FOREIGN KEY (FKID) REFERENCES T1 (ID);  --succeeds

ALTER TABLE T2 CHECK CONSTRAINT FK_T2_T1;   --succeeds since the CONSTRAINT is attributed as NOCHECK

--Attempt to enable CONSTRAINT fails due to orphans

ALTER TABLE T2 WITH CHECK CHECK CONSTRAINT FK_T2_T1;    --fails

--Remove orphans

DELETE FROM T2 WHERE FKID NOT IN (SELECT ID FROM T1);

--Enabling the CONSTRAINT succeeds

ALTER TABLE T2 WITH CHECK CHECK CONSTRAINT FK_T2_T1;    --succeeds; orphans removed

--Clean up

DROP TABLE T2;

DROP TABLE T1;

Performance killing:

SQL SERVER – User Defined Functions (UDF) Limitations

UDF have its own advantage and usage but in this article we will see the limitation of UDF (Things UDF cannot do) and why Stored Procedure is considered as more flexible then UDFs.

Stored Procedure has more flexibility then User Defined Functions (UDF).

·         UDF has No Access to Structural and Permanent Tables.

o    UDF can call Extended Stored Procedure, which can have access to structural and permanent tables. (No Access to Stored Procedure)

• UDF Prohibit Usage of Non-Deterministic Built-in Functions

• Functions GETDATE() etc cannot be used UDFs, but can be used in Stored Procedure

• UDF Returns Only One Result Set or Output Parameter

• Due to this it can be used in SELECT statement but cannot return multiple result set like Stored Procedure

• UDF cannot Call Stored Procedure

• Only access to Extended Stored Procedure.

• UDF cannot Execute Dynamic SQL or Temporary Tables

• UDF cannot run dynamic SQL which are dynamically built in UDF. Temporary Tables cannot be used in UDF as well.

• UDF cannot Return XML

• FOR XML is not allowed in UDF

• UDF does not support SET options

• SET options which can change Server level or transaction level settings are prohibited in UDFs. (SET ROWCOUNT etc)

• UDF does not Support Error Handling

• RAISEERROR or @@ERROR are not allowed in UDFs.

Microsoft SQL Server   Interview Questions (FAQs)

Transact-SQL Optimization

Use views and stored procedures instead of heavy-duty queries.

This can reduce network traffic, because your client will send to server only stored procedure or view name (perhaps with some parameters) instead of large heavy-duty queries text. This can be used to facilitate permission management also, because you can restrict user access to table columns they should not see.

·         Try to use constraints instead of triggers, whenever possible.

Constraints are much more efficient than triggers and can boost performance. So, you should use constraints instead of triggers, whenever possible.

·         Use table variables instead of temporary tables.

Table variables require less locking and logging resources than temporary tables, so table variables should be used whenever possible. The table variables are available in SQL Server 2000 only.

·         Try to use UNION ALL statement instead of UNION, whenever possible.

The UNION ALL statement is much faster than UNION, because UNION ALL statement does not look for duplicate rows, and UNION statement does look for duplicate rows, whether or not they exist.

·         Try to avoid using the DISTINCT clause, whenever possible.

Because using the DISTINCT clause will result in some performance degradation, you should use this clause only when it is necessary.

·         Try to avoid using SQL Server cursors, whenever possible.

SQL Server cursors can result in some performance degradation in comparison with select statements. Try to use correlated sub-query or derived tables, if you need to perform row-by-row operations.

·         Try to avoid the HAVING clause, whenever possible.

The HAVING clause is used to restrict the result set returned by the GROUP BY clause. When you use GROUP BY with the HAVING clause, the GROUP BY clause divides the rows into sets of grouped rows and aggregates their values, and then the HAVING clause eliminates undesired aggregated groups. In many cases, you can write your select statement so, that it will contain only WHERE and GROUP BY clauses without HAVING clause. This can improve the performance of your query.

·         If you need to return the total table's row count, you can use alternative way instead of SELECT COUNT (*) statement.

Because SELECT COUNT (*) statement makes a full table scan to return the total table's row count, it can take very many time for the large table. There is another way to determine the total row count in a table. You can use sysindexes system table, in this case. There is ROWS column in the sysindexes table. This column contains the total row count for each table in your database. So, you can use the following select statement instead of SELECT COUNT (*):

SELECT rows FROM sysindexes WHERE id = OBJECT_ID ('table_name') AND indid < 2 So, you can improve the speed of such queries in several times. 

·         Include SET NOCOUNT ON statement into your stored procedures to stop the message indicating the number of rows affected by a T-SQL statement.

This can reduce network traffic, because your client will not receive the message indicating the number of rows affected by a T-SQL statement.

·         Try to restrict the queries result set by using the WHERE clause.

This can results in good performance benefits, because SQL Server will return to client only particular rows, not all rows from the table(s). This can reduce network traffic and boost the overall performance of the query.

·   Use the select statements with TOP keyword or the SET ROWCOUNT statement, if you need to return only the first n rows.

This can improve performance of your queries, because the smaller result set will be returned. This can also reduce the traffic between the server and the clients.

·   Try to restrict the queries result set by returning only the particular columns from the table, not all table's columns.

This can results in good performance benefits, because SQL Server will return to client only particular columns, not all table's columns. This can reduce network traffic and boost the overall performance of the query.

1.Indexes
2.avoid more number of triggers on the table
3.unnecessary complicated joins
4.correct use of Group by clause with the select list
5.in worst cases Denormalization

T-SQL Queries

1. 2 tables

Employee	Phone
empid empname salary mgrid	empid phnumber

1. Select all employees who doesn't have phone?
SELECT empname FROM Employee WHERE empid NOT IN    (SELECT DISTINCT mpid FROM phone)

2.            Select the employee names who is having more than one phone numbers.

3.    SELECT empname FROM employee WHERE (empid IN (SELECT empid
FROM phone GROUP BY empid HAVING COUNT (empid) > 1))

4.    Select the details of 3 max salaried employees from employee table.
SELECT TOP 3 empid, salary FROM employee ORDER BY salary DESC

5.        Display all managers from the table.(manager id is same as emp id)
SELECT empname FROM employee WHERE (empid IN (SELECT DISTINCT mgrid FROM employee))

6.        Write a Select statement to list the Employee Name, Manager Name under a particular manager?
SELECT e1.empname AS EmpName, e2.empname AS ManagerName
FROM Employee e1 INNER JOIN Employee e2 ON e1.mgrid = e2.empid
ORDER BY e2.mgrid

7.        2 tables emp and phone. emp fields are - empid, name, Ph fields are - empid, ph (office, mobile, home). Select all employees who don’t have any ph nos.
SELECT * FROM employee LEFT OUTER JOIN phone ON employee.empid =phone.empid WHERE (phone. office IS NULL OR phone.office = ' ')
AND (phone.mobile IS NULL OR phone.mobile = ' ')
AND (phone.home IS NULL OR phone.home = ' ')

8.        Find employee who is living in more than one city.  Two Tables:

Emp	City
Empid empName Salary	Empid City

SELECT empname, fname, lname FROM employee WHERE (empid IN (SELECT empid FROM city GROUP BY empid HAVING COUNT (empid) > 1))

9.        Find all employees who are living in the same city. (table is same as above)
SELECT fname FROM employee WHERE (empid IN  (SELECT empid
FROM city a  WHERE city IN (SELECT city FROM city b GROUP BY city HAVING COUNT(city) > 1)))

10.      There is a table named MovieTable with three columns - moviename, person and role. Write a query which gets the movie details where Mr. Amitabh and Mr. Vinod acted and their role is actor.
SELECT DISTINCT m1.moviename FROM MovieTable m1 INNER JOIN
MovieTable m2 ON m1.moviename = m2.moviename WHERE (m1.person = 'amitabh' AND m2.person = 'vinod' OR m2.person = 'amitabh' AND m1.person = 'vinod') AND (m1.role = 'actor') AND (m2.role = 'actor') ORDER BY m1.moviename

11.      There are two employee tables named emp1 and emp2. Both contains same structure (salary details). But Emp2 salary details are incorrect and emp1 salary details are correct. So, write a query which corrects salary details of the table emp2
update a set a.sal=b.sal from emp1 a, emp2 b where a.empid=b.empid

12.      Given a Table named “Students” which contains studentid, subjectid and marks. Where there are 10 subjects and 50 students. Write a Query to find out the Maximum marks obtained in each subject.

13.      In this same tables now write a SQL Query to get the studentid also to combine with previous results.

14.      Three tables – student , course, marks – how do go at finding name of the students who got max marks in the diff courses.
SELECT student.name, course.name AS coursename, marks.sid, marks.mark FROM marks INNER JOIN student ON marks.sid = student.sid INNER JOIN course ON marks.cid = course.cid
WHERE (marks.mark = (SELECT MAX(Mark)
FROM Marks MaxMark WHERE MaxMark.cID = Marks.cID))

15.      There is a table day_temp which has three columns dayid, day and temperature. How do I write a query to get the difference of temperature among each other for seven days of a week?
SELECT a.dayid, a.dday, a.tempe, a.tempe - b.tempe AS Difference FROM day_temp a INNER JOIN day_temp b ON a.dayid = b.dayid + 1 OR
Select a.day, a.degree-b.degree from temperature a, temperature b where a.id=b.id+1

16.      There is a table which contains the names like this. a1, a2, a3, a3, a4, a1, a1, a2 and their salaries. Write a query to get grand total salary, and total salaries of individual employees in one query.
SELECT empid, SUM(salary) AS salary FROM employee
GROUP BY empid WITH ROLLUP ORDER BY empid

17.      How to know how many tables contains empno as a column in a database?
SELECT COUNT(*) AS Counter FROM syscolumns
WHERE (name = 'empno') 

18.      Find duplicate rows in a table? OR I have a table with one column which has many records which are not distinct. I need to find the distinct values from that column and number of times it’s repeated.
SELECT sid, mark, COUNT(*) AS Counter FROM marks GROUP BY sid, mark HAVING (COUNT(*) > 1)

19.      How to delete the rows which are duplicate (don’t delete both duplicate records).
SET ROWCOUNT 1

20.      DELETE yourtable FROM yourtable a
WHERE (SELECT COUNT(*) FROM yourtable b WHERE b.name1 = a.name1 AND b.age1 = a.age1) > 1 WHILE @@rowcount > 0 DELETE yourtable   FROM yourtable a WHERE (SELECT COUNT(*) FROM yourtable b WHERE b.name1 = a.name1 AND b.age1 = a.age1) > 1
SET ROWCOUNT 0

21.      How to find 6th highest salary
SELECT TOP 1 salary FROM (SELECT DISTINCT TOP 6 salary
FROM employee ORDER BY salary DESC) a ORDER BY salary

22.      Find top salary among two tables
SELECT TOP 1 sal FROM (SELECT MAX(sal) AS sal FROM sal1 UNION SELECT MAX(sal) AS sal FROM sal2) a ORDER BY sal DESC 

23.      Write a query to convert all the letters in a word to upper case
SELECT UPPER('test')

24.      Write a query to round up the values of a number. For example even if the user enters 7.1 it should be rounded up to 8.
SELECT CEILING (7.1)

25.      Write a SQL Query to find first day of month?
SELECT DATENAME (dw, DATEADD (dd, - DATEPART (dd, GETDATE ()) + 1, GETDATE ())) AS FirstDay

Datepart	Abbreviations
year	yy, yyyy
quarter	qq, q
month	mm, m
dayofyear	dy, y
day	dd, d
week	wk, ww
weekday	Dw
hour	Hh
minute	mi, n
second	ss, s
millisecond	Ms

26.      Table A contains column1 which is primary key and has 2 values (1, 2) and Table B contains column1 which is primary key and has 2 values (2, 3). Write a query which returns the values that are not common for the tables and the query should return one column with 2 records.
SELECT tbla.a FROM tbla, tblb WHERE tbla.a <> (SELECT tblb.a
FROM tbla, tblb WHERE tbla.a = tblb.a) UNION SELECT tblb.a
FROM tbla, tblb WHERE tblb.a <> (SELECT tbla.a FROM tbla, tblb
WHERE tbla.a = tblb.a)

OR (better approach)

SELECT a FROM tbla WHERE a NOT IN (SELECT a FROM tblb)
UNION ALL SELECT a FROM tblb WHERE a NOT IN (SELECT a FROM tbla)

27.      There are 3 tables Titles, Authors and Title-Authors (check PUBS db). Write the query to get the author name and the number of books written by that author, the result should start from the author who has written the maximum number of books and end with the author who has written the minimum number of books.
SELECT authors.au_lname, COUNT(*) AS BooksCount FROM authors INNER JOIN
titleauthor ON authors.au_id = titleauthor.au_id INNER JOIN
titles ON titles.title_id = titleauthor.title_id GROUP BY authors.au_lname ORDER BY BooksCount DESC

28.      List all products with total quantity ordered, if quantity ordered is null show it as 0.
SELECT name, CASE WHEN SUM(qty) IS NULL THEN 0 WHEN SUM(qty)> 0 THEN SUM(qty) END AS tot FROM [order] RIGHT OUTER JOIN
product ON [order].prodid = product.prodid GROUP BY name
Result:
coke 60
mirinda 0
pepsi 10

29.      ANY, SOME, or ALL?cxx
ALL means greater than every value--in other words, greater than the maximum value. For example, >ALL (1, 2, 3) means greater than 3.
ANY means greater than at least one value, that is, greater than the minimum. So >ANY (1, 2, 3) means greater than 1. SOME is an SQL-92 standard equivalent for ANY.

o      IN & = (difference in correlated sub query)
 

30.      Given a scenario that I have a 10 Clustered Index in a Table to all their 10 Columns. What are the advantages and disadvantages?
A: Only 1 clustered index is possible.

31.      How can I enforce to use particular index?
You can use index hint (index=<index_name>) after the table name.
SELECT au_lname FROM authors (index=aunmind)

32.      What is sorting and what is the difference between sorting & clustered indexes?
The ORDER BY clause sorts query results by one or more columns up to 8,060 bytes. This will happen by the time when we retrieve data from database. Clustered indexes physically sorting data, while inserting/updating the table.

33.      Difference between char and nvarchar / char and varchar data-type?
char[(n)] - Fixed-length non-Unicode character data with length of n bytes. n must be a value from 1 through 8,000. Storage size is n bytes. The SQL-92 synonym for char is character.
nvarchar(n) - Variable-length Unicode character data of n characters. n must be a value from 1 through 4,000. Storage size, in bytes, is two times the number of characters entered. The data entered can be 0 characters in length. The SQL-92 synonyms for nvarchar are national char varying and national character varying.
varchar[(n)] - Variable-length non-Unicode character data with length of n bytes. n must be a value from 1 through 8,000. Storage size is the actual length in bytes of the data entered, not n bytes. The data entered can be 0 characters in length. The SQL-92 synonyms for varchar are char varying or character varying.

34.      GUID datasize?
128bit

35.      How GUID becoming unique across machines?
To ensure uniqueness across machines, the ID of the network card is used (among others) to compute the number.

36.      Can I improve performance by using the ANSI-style joins instead of the old-style joins?
Code Example 1:
select o.name, i.name from sysobjects o, sysindexes i
where o.id = i.id

Code Example 2:
select o.name, i.name from sysobjects o inner join sysindexes i
on o.id = i.id

You will not get any performance gain by switching to the ANSI-style JOIN syntax.
Using the ANSI-JOIN syntax gives you an important advantage:

Because the join logic is cleanly separated from the filtering criteria, you can understand the query logic more quickly.
The SQL Server old-style JOIN executes the filtering conditions before executing the joins, whereas the ANSI-style JOIN reverses this procedure (join logic precedes filtering).
Perhaps the most compelling argument for switching to the ANSI-style JOIN is that Microsoft has explicitly stated that SQL Server will not support the old-style OUTER JOIN syntax indefinitely. Another important consideration is that the ANSI-style JOIN supports query constructions that the old-style JOIN syntax does not support.

37.      How do I mark the stored procedure to automatic execution?
You can use the sp_procoption system stored procedure to mark the stored procedure to automatic execution when the SQL Server will start. Only objects in the master database owned by dbo can have the startup setting changed and this option is restricted to objects that have no parameters.
USE master
EXEC sp_procoption 'indRebuild', 'startup', 'true')

38.      How will know whether the SQL statements are executed?
When used in a stored procedure, the RETURN statement can specify an integer value to return to the calling application, batch, or procedure. If no value is specified on RETURN, a stored procedure returns the value 0.  The stored procedures return a value of 0 when no errors were encountered. Any nonzero value indicates an error occurred.

39.      Why one should not prefix user stored procedures with sp_?
It is strongly recommended that you do not create any stored procedures using sp_ as a prefix. SQL Server always looks for a stored procedure beginning with sp_ in this order:

·                                                   The stored procedure in the master database.

·                                                   The stored procedure based on any qualifiers provided (database name or owner).

·                                                   The stored procedure using dbo as the owner, if one is not specified.

         Therefore, although the user-created stored procedure prefixed with sp_ may exist in the current database, the master database is always checked first, even if the stored procedure is qualified with the database name.

40.      What can cause a Stored procedure execution plan to become invalidated and/or fall out of cache?

0.        Server restart

1.        Plan is aged out due to low use

2.        DBCC FREEPROCCACHE (sometime desired to force it)

41.      When do one need to recompile stored procedure?
if a new index is added from which the stored procedure might benefit, optimization does not automatically happen (until the next time the stored procedure is run after SQL Server is restarted).

42.      I have Two Stored Procedures SP1 and SP2 as given below. How the Transaction works, whether SP2 Transaction succeeds or fails?
CREATE PROCEDURE SP1 AS
BEGIN TRAN
    INSERT INTO MARKS (SID,MARK,CID) VALUES (5,6,3)
EXEC SP2
ROLLBACK
GO

CREATE PROCEDURE SP2 AS
BEGIN TRAN
INSERT INTO MARKS (SID,MARK,CID) VALUES (100,100,103)
commit tran
GO
Both will get roll backed.

43.      CREATE PROCEDURE SP1 AS
BEGIN TRAN
    INSERT INTO MARKS (SID,MARK,CID) VALUES (5,6,3)
    BEGIN TRAN
        INSERT INTO STUDENT (SID,NAME1) VALUES (1,'SA')
    commit tran
ROLLBACK TRAN
GO
Both will get roll backed.

44.      How will you handle Errors in SQL Stored Procedure?
INSERT NonFatal VALUES (@Column2)
IF @@ERROR <>0
 BEGIN
  PRINT 'Error Occured'
 END
 

45.      How will you raise an error in SQL?
RAISERROR –

Returns a user-defined error message and sets a system flag to record that an error has occurred. Using RAISERROR, the client can either retrieve an entry from the sysmessages table or build a message dynamically with user-specified severity and state information. After the message is defined it is sent back to the client as a server error message.

46.      I have a stored procedure like
commit tran
create table a()
insert into table b
--
--
rollback tran
what will be the result? Is table created? data will be inserted in table b?

47.      How you will return XML from Stored Procedure?
You use the FOR XML clause of the SELECT statement, and within the FOR XML clause you specify an XML mode: RAW, AUTO, or EXPLICIT.

48.      Can a Stored Procedure call itself (recursive). If so then up to what level and can it be control?
Stored procedures are nested when one stored procedure calls another. You can nest stored procedures up to 32 levels. The nesting level increases by one when the called stored procedure begins execution and decreases by one when the called stored procedure completes execution. Attempting to exceed the maximum of 32 levels of nesting causes the whole calling stored procedure chain to fail. The current nesting level for the stored procedures in execution is stored in the @@NESTLEVEL function.
eg:
SET NOCOUNT ON
USE master
IF OBJECT_ID('dbo.sp_calcfactorial') IS NOT NULL
DROP PROC dbo.sp_calcfactorial
GO
CREATE PROC dbo.sp_calcfactorial
@base_number int, @factorial int OUT
AS
DECLARE @previous_number int
IF (@base_number<2) SET @factorial=1 -- Factorial of 0 or 1=1
ELSE BEGIN
SET @previous_number=@base_number-1
EXEC dbo.sp_calcfactorial @previous_number, @factorial OUT -- Recursive call
IF (@factorial=-1) RETURN(-1) -- Got an error, return
SET @factorial=@factorial*@base_number
END
RETURN(0)
GO

calling proc.
DECLARE @factorial int
EXEC dbo.sp_calcfactorial 4, @factorial OUT
SELECT @factorial

49.      Nested Triggers
Triggers are nested when a trigger performs an action that initiates another trigger, which can initiate another trigger, and so on. Triggers can be nested up to 32 levels, and you can control whether triggers can be nested through the nested triggers server configuration option.

50.      What is an extended stored procedure? Can you instantiate a COM object by using T-SQL?
An extended stored procedure is a function within a DLL (written in a programming language like C, C++ using Open Data Services (ODS) API) that can be called from T-SQL, just the way we call normal stored procedures using the EXEC statement.

51.      Difference between view and stored procedure?
Views can have only select statements (create, update, truncate, delete statements are not allowed) Views cannot have “select into”, “Group by” “Having”, ”Order by”

52.      Difference between trigger and stored procedure?
Trigger will get execute automatically when an UPDATE, INSERT, or DELETE statement is issued against a table or view.
We have to call stored procedure manually, or it can execute automatic when the SQL Server starts (You can use the sp_procoption system stored procedure to mark the stored procedure to automatic execution when the SQL Server will start.

53.      The following trigger generates an e-mail whenever a new title is added.
CREATE TRIGGER reminder
ON titles
FOR INSERT
AS
EXEC master..xp_sendmail 'MaryM', 'New title, mention in the next report to distributors.'

54.      Drawback of trigger? Its alternative solution?
Triggers are generally used to implement business rules, auditing. Triggers can also be used to extend the referential integrity checks, but wherever possible, use constraints for this purpose, instead of triggers, as constraints are much faster.

55.      Does the View occupy memory space? No

56.      Can u drop a table if it has a view?
Views or tables participating in a view created with the SCHEMABINDING clause cannot be dropped. If the view is not created using SCHEMABINDING, then we can drop the table.

57.      Why doesn't SQL Server permit an ORDER BY clause in the definition of a view?
SQL Server excludes an ORDER BY clause from a view to comply with the ANSI SQL-92 standard. Because analyzing the rationale for this standard requires a discussion of the underlying structure of the structured query language (SQL) and the mathematics upon which it is based, we can't fully explain the restriction here. However, if you need to be able to specify an ORDER BY clause in a view, consider using the following workaround
USE pubs
GO
CREATE VIEW AuthorsByName
AS
SELECT TOP 100 PERCENT * FROM authors  ORDER BY au_lname, au_fname
GO
The TOP construct, which Microsoft introduced in SQL Server 7.0, is most useful when you combine it with the ORDER BY clause. The only time that SQL Server supports an ORDER BY clause in a view is when it is used in conjunction with the TOP keyword. (Note that the TOP keyword is a SQL Server extension to the ANSI SQL-92 standard.)

TRANSACTION

58.      What is Transaction?
A transaction is a sequence of operations performed as a single logical unit of work. A logical unit of work must exhibit four properties, called the ACID (Atomicity, Consistency, Isolation, and Durability) properties, to qualify as a transaction:

·               Atomicity - A transaction must be an atomic unit of work; either all of its data modifications are performed or none of them is performed.

·               Consistency - When completed, a transaction must leave all data in a consistent state. In a relational database, all rules must be applied to the transaction's modifications to maintain all data integrity. All internal data structures, such as B-tree indexes or doubly-linked lists, must be correct at the end of the transaction.

·               Isolation - Modifications made by concurrent transactions must be isolated from the modifications made by any other concurrent transactions. A transaction either sees data in the state it was in before another concurrent transaction modified it, or it sees the data after the second transaction has completed, but it does not see an intermediate state. This is referred to as serializability because it results in the ability to reload the starting data and replay a series of transactions to end up with the data in the same state it was in after the original transactions were performed.

·               Durability - After a transaction has completed, its effects are permanently in place in the system. The modifications persist even in the event of a system failure.

59.      After one Begin Transaction a truncate statement and a RollBack statements are there. Will it be rollbacked? Since the truncate statement does not perform logged operation how does it RollBack?
It will rollback.
**

60.      Given a SQL like
Begin Tran
   Select @@Rowcount
Begin Tran
   Select @@Rowcount
Begin Tran
   Select @@Rowcount
Commit Tran
   Select @@Rowcount
RollBack
   Select @@Rowcount
RollBack
   Select @@Rowcount
What is the value of @@Rowcount at each stmt levels?
Ans : 0 – zero.
@@ROWCOUNT - Returns the number of rows affected by the last statement.
@@TRANCOUNT - Returns the number of active transactions for the current connection.
Each Begin Tran will add count, each commit will reduce count and ONE rollback will make it 0.

OTHER

61.      What are the constraints for Table Constraints define rules regarding the values allowed in columns and are the standard mechanism for enforcing integrity. SQL Server 2000 supports five classes of constraints.
NOT NULL
CHECK
UNIQUE
PRIMARY KEY
FOREIGN KEY

62.      There are 50 columns in a table. Write a query to get first 25 columns
Ans: Need to mention each column names.

63.      How to list all the tables in a particular database?
USE pubs
GO
sp_help

64.      What is Dynamic Cursor? Suppose, I have a dynamic cursor attached to table in a database.  I have another means by which I will modify the table.  What do you think will the values in the cursor be?
Dynamic cursors reflect all changes made to the rows in their result set when scrolling through the cursor. The data values, order, and membership of the rows in the result set can change on each fetch. All UPDATE, INSERT, and DELETE statements made by all users are visible through the cursor. Updates are visible immediately if they are made through the cursor using either an API function such as SQLSetPos or the Transact-SQL WHERE CURRENT OF clause. Updates made outside the cursor are not visible until they are committed, unless the cursor transaction isolation level is set to read uncommitted.

65.      What is DATEPART?
Returns an integer representing the specified datepart of the specified date.

66.      Difference between Delete and Truncate?
TRUNCATE TABLE is functionally identical to DELETE statement with no WHERE clause: both remove all rows in the table.
(1) But TRUNCATE TABLE is faster and uses fewer system and transaction log resources than DELETE. The DELETE statement removes rows one at a time and records an entry in the transaction log for each deleted row. TRUNCATE TABLE removes the data by deallocating the data pages used to store the table's data, and only the page deallocations are recorded in the transaction log.
(2) Because TRUNCATE TABLE is not logged, it cannot activate a trigger.
(3) The counter used by an identity for new rows is reset to the seed for the column. If you want to retain the identity counter, use DELETE instead.
Of course, TRUNCATE TABLE can be rolled back.

67.      What are global variables? Tell me some of them?
Transact-SQL global variables are a form of function and are now referred to as functions.
ABS - Returns the absolute, positive value of the given numeric expression.
SUM, AVG, AND

68.      What is DDL?
Data definition language (DDL) statements are SQL statements that support the definition or declaration of database objects (for example, CREATE TABLE, DROP TABLE, and ALTER TABLE).
You can use the ADO Command object to issue DDL statements. To differentiate DDL statements from a table or stored procedure name, set the CommandType property of the Command object to adCmdText. Because executing DDL queries with this method does not generate any recordsets, there is no need for a Recordset object.

69.      What is DML?
Data Manipulation Language (DML), which is used to select, insert, update, and delete data in the objects defined using DDL

70.      What are keys in RDBMS? What is a primary key/ foreign key?
There are two kinds of keys.
A primary key is a set of columns from a table that are guaranteed to have unique values for each row of that table.
Foreign keys are attributes of one table that have matching values in a primary key in another table, allowing for relationships between tables.

71.      What is the difference between Primary Key and Unique Key?
Both primary key and unique key enforce uniqueness of the column on which they are defined. But by default primary key creates a clustered index on the column, where are unique creates a nonclustered index by default. Another major difference is that, primary key doesn't allow NULLs, but unique key allows one NULL only.

72.      Define candidate key, alternate key, composite key?
A candidate key is one that can identify each row of a table uniquely. Generally a candidate key becomes the primary key of the table. If the table has more than one candidate key, one of them will become the primary key, and the rest are called alternate keys.
A key formed by combining at least two or more columns is called composite key.

73.      What is the Referential Integrity?
Referential integrity refers to the consistency that must be maintained between primary and foreign keys, i.e. every foreign key value must have a corresponding primary key value.

74.      What are defaults? Is there a column to which a default can't be bound?
A default is a value that will be used by a column, if no value is supplied to that column while inserting data. IDENTITY columns and timestamp columns can't have defaults bound to them.

75.      What is the use of shell commands? xp_cmdshell
Executes a given command string as an operating-system command shell and returns any output as rows of text. Grants nonadministrative users permissions to execute xp_cmdshell.

76.      What is use of shrink database?
Microsoft® SQL Server 2000 allows each file within a database to be shrunk to remove unused pages. Both data and transaction log files can be shrunk.

77.      How do you differentiate Local and Global Temporary table?
You can create local and global temporary tables. Local temporary tables are visible only in the current session; global temporary tables are visible to all sessions. Prefix local temporary table names with single number sign (#table_name), and prefix global temporary table names with a double number sign (##table_name). SQL statements reference the temporary table using the value specified for table_name in the CREATE TABLE statement:
CREATE TABLE #MyTempTable (cola INT PRIMARY KEY)
INSERT INTO #MyTempTable VALUES (1)

78.      How the Exists keyword works in SQL Server?
USE pubs
SELECT au_lname, au_fname FROM authors WHERE exists (SELECT *
   FROM publishers  WHERE authors.city = publishers.city)
When a subquery is introduced with the keyword EXISTS, it functions as an existence test. The WHERE clause of the outer query tests for the existence of rows returned by the subquery. The subquery does not actually produce any data; it returns a value of TRUE or FALSE.

79.      ANY?
USE pubs
SELECT au_lname, au_fname FROM authors WHERE city = ANY
(SELECT city FROM publishers)

80.      To select date part only
SELECT CONVERT(char(10),GetDate(),101)
--to select time part only
SELECT right(GetDate(),7)

81.      What is normalization? Explain different levels of normalization? Explain Third normalization form with an example?
The process of refining tables, keys, columns, and relationships to create an efficient database is called normalization. This should eliminates unnecessary duplication and provides a rapid search path to all necessary information.
Some of the benefits of normalization are:

·   Data integrity (because there is no redundant, neglected data)

·   Optimized queries (because normalized tables produce rapid, efficient joins)

·   Faster index creation and sorting (because the tables have fewer columns)

·   Faster UPDATE performance (because there are fewer indexes per table)

·   Improved concurrency resolution (because table locks will affect less data)

·   Eliminate redundancy

         There are a few rules for database normalization. Each rule is called a "normal form." If the first rule is observed, the database is said to be in "first normal form." If the first three rules are observed, the database is considered to be in "third normal form." Although other levels of normalization are possible, third normal form is considered the highest level necessary for most applications.

         First Normal Form (1NF)

·         Eliminate repeating groups in individual tables

·         Create a separate table for each set of related data.

·         Identify each set of related data with a primary key.

         Do not use multiple fields in a single table to store similar data.
Example

	Subordinate1	Subordinate2	Subordinate3	Subordinate4
Bob	Jim	Mary	Beth
Mary	Mike	Jason	Carol	Mark
Jim	Alan

Eliminate duplicative columns from the same table.  Clearly, the Subordinate1 Subordinate4 Columns are duplicative. What happens when we need to add or remove a subordinate?

	Subordinates
Bob	Jim, Mary, Beth
Mary	Mike, Jason, Carol, Mark
Jim	Alan

This solution is closer, but it also falls short of the mark. The subordinates column is still duplicative and non-atomic. What happens when we need to add or remove a subordinate? We need to read and write the entire contents of the table. That’s not a big deal in this situation, but what if one manager had one hundred employees? Also, it complicates the process of selecting data from the database in future queries.

         Solution:

	Subordinate
Bob	Jim
Bob	Mary
Bob	Beth
Mary	Mike
Mary	Jason
Mary	Carol
Mary	Mark
Jim	Alan

         Second Normal Form (2NF)

·         Create separate tables for sets of values that apply to multiple records.

·         Relate these tables with a foreign key.

Records should not depend on anything other than a table's primary key (a compound key, if necessary).

For example, consider a customer's address in an accounting system. The address is needed by the Customers table, but also by the Orders, Shipping, Invoices, Accounts Receivable, and Collections tables. Instead of storing the customer's address as a separate entry in each of these tables, store it in one place, either in the Customers table or in a separate Addresses table. 

Third Normal Form (3NF)

·               Eliminate fields that do not depend on the key.

Values in a record that are not part of that record's key do not belong in the table. In general, any time the contents of a group of fields may apply to more than a single record in the table, consider placing those fields in a separate table.
For example, in an Employee Recruitment table, a candidate's university name and address may be included. But you need a complete list of universities for group mailings. If university information is stored in the Candidates table, there is no way to list universities with no current candidates. Create a separate Universities table and link it to the Candidates table with a university code key.
Another Example :

MemberId	Name	Company	CompanyLoc
1	John Smith	ABC	Alabama
2	Dave Jones	MCI	Florida

The Member table satisfies first normal form - it contains no repeating groups. It satisfies second normal form - since it doesn't have a multivalued key. But the key is MemberID, and the company name and location describe only a company, not a member. To achieve third normal form, they must be moved into a separate table. Since they describe a company, CompanyCode becomes the key of the new "Company" table.

The motivation for this is the same for second normal form: we want to avoid update and delete anomalies. For example, suppose no members from the IBM were currently stored in the database. With the previous design, there would be no record of its existence, even though 20 past members were from IBM.

         Member Table

MemberId	Name	CID
1	John Smith	1
2	Dave Jones	2

         Company Table

Cid	Name	Location
1	ABC	Alabama
2	MCI	Florida

Boyce-Codd Normal Form (BCNF)
A relation is in Boyce/Codd normal form if and only if the only determinants are candidate key. Its a different version of 3NF, indeed, was meant to replace it. [A determinant is any attribute on which some other attribute is (fully) functionally dependent.]

4th Normal Form (4NF)

A table is in 4NF if it is in BCNF and if it has no multi-valued dependencies. This applies primarily to key-only associative tables, and appears as a ternary relationship, but has incorrectly merged 2 distinct, independent relationships.
Eg: This could be any 2 M:M relationships from a single entity. For instance, a member could know many software tools, and a software tool may be used by many members. Also, a member could have recommended many books, and a book could be recommended by many members.

Software

Member

Book

The correct solution, to cause the model to be in 4th normal form, is to ensure that all M:M relationships are resolved independently if they are indeed independent.

Software

Member software

Member

Member Book

Book

5th Normal Form (5NF)(PJNF)
A table is in 5NF, also called "Projection-Join Normal Form", if it is in 4NF and if every join dependency in the table is a consequence of the candidate keys of the table.

Domain/Key Normal form (DKNF). A key uniquely identifies each row in a table. A domain is the set of permissible values for an attribute. By enforcing key and domain restrictions, the database is assured of being freed from modification anomalies. DKNF is the normalization level that most designers aim to achieve.

Remember, these normalization guidelines are cumulative.  For a database to be in 2NF, it must first fulfill all the criteria of a 1NF database.

82.      What is denormalization and when would you go for it?
As the name indicates, denormalization is the reverse process of normalization. It's the controlled introduction of redundancy in to the database design. It helps improve the query performance as the number of joins could be reduced.

83.      How can I randomly sort query results?
To randomly order rows, or to return x number of randomly chosen rows, you can use the RAND function inside the SELECT statement. But the RAND function is resolved only once for the entire query, so every row will get same value. You can use an ORDER BY clause to sort the rows by the result from the NEWID function, as the following code shows:
SELECT * FROM Northwind..Orders ORDER BY NEWID()

84.      sp_who
Provides information about current Microsoft® SQL Server™ users and processes. The information returned can be filtered to return only those processes that are not idle.

85.      How to find dependents of a table?
Verify dependencies with sp_depends before dropping an object

86.      What is the difference between a CONSTRAINT AND RULE?
Rules are a backward-compatibility feature that perform some of the same functions as CHECK constraints. CHECK constraints are the preferred, standard way to restrict the values in a column. CHECK constraints are also more concise than rules; there can only be  one rule applied to a column, but multiple CHECK constraints can be applied. CHECK constraints are specified as part of the CREATE TABLE statement, while rules are created as separate objects and then bound to the column.

87.      How to call a COM dll from SQL Server 2000?
sp_OACreate - Creates an instance of the OLE object on an instance of Microsoft® SQL Server
Syntax
sp_OACreate progid, | clsid,
    objecttoken OUTPUT
    [ , context ]

context - Specifies the execution context in which the newly created OLE object runs. If specified, this value must be one of the following:
1 = In-process (.dll) OLE server only
4 = Local (.exe) OLE server only
5 = Both in-process and local OLE server allowed

Examples

A. Use Prog ID - This example creates a SQL-DMO SQLServer object by using its ProgID.

DECLARE @object int

DECLARE @hr int

DECLARE @src varchar(255), @desc varchar(255)

EXEC @hr = sp_OACreate 'SQLDMO.SQLServer', @object OUT

IF @hr <> 0

BEGIN

   EXEC sp_OAGetErrorInfo @object, @src OUT, @desc OUT 

   SELECT hr=convert(varbinary(4),@hr), Source=@src, Description=@desc

    RETURN

END

B. Use CLSID - This example creates a SQL-DMO SQLServer object by using its CLSID.

DECLARE @object int

DECLARE @hr int

DECLARE @src varchar(255), @desc varchar(255)

EXEC @hr = sp_OACreate '{00026BA1-0000-0000-C000-000000000046}',

    @object OUT

IF @hr <> 0

BEGIN

   EXEC sp_OAGetErrorInfo @object, @src OUT, @desc OUT 

   SELECT hr=convert(varbinary(4),@hr), Source=@src, Description=@desc

    RETURN

END

88.      Difference between sysusers and syslogins?
sysusers - Contains one row for each Microsoft® Windows user, Windows group, Microsoft SQL Server™ user, or SQL Server role in the database.
syslogins - Contains one row for each login account.

89.      What is the row size in SQL Server 2000?
8060 bytes.

90.      How will you find structure of table, all tables/views in one db, all dbs?
//structure of table
sp_helpdb tbl_emp

//list of all databases
sp_helpdb
OR
SELECT * FROM master.dbo.sysdatabases

//details about database pubs. .mdf, .ldf file locations, size of database
sp_helpdb pubs

//lists all tables under current database
sp_tables
OR
SELECT * FROM information_schema.tables WHERE (table_type = 'base table')
OR
SELECT * FROM sysobjects WHERE type = 'U' //faster

91.      What is the system function to get the current user's user id?
USER_ID(). Also check out other system functions like USER_NAME(), SYSTEM_USER, SESSION_USER, CURRENT_USER, USER, SUSER_SID(), HOST_NAME().

92.      What are the series of steps that happen on execution of a query in a Query Analyzer?
1) Syntax checking 2) Parsing 3) Execution plan

93.      Which event (Check constraints, Foreign Key, Rule, trigger, Primary key check) will be performed last for integrity check?
Identity Insert Check
Nullability constraint
Data type check
Instead of trigger
Primary key
Check constraint
Foreign key
DML Execution (update statements)
After Trigger
**

94.      How will you show many to many relation in SQL?
Create 3rd table with 2 columns which having one to many relation to these tables.

95.      When a query is sent to the database and an index is not being used, what type of execution is taking place?
A table scan.

96.      What is #, ##, @, @@ means?
1) @@ - System variables 2) @ - user defined variables

97.      What is the difference between a Local temporary table and a Global temporary table? How is each one denoted?
Local temporary table will be accessible to only current user session, its name will be preceded with a single hash (#mytable)
Global temporary table will be accessible to all users, & it will be dropped only after ending of all active connections, its name will be preceded with double hash (##mytable)

TOOLS 

98.      What is the output of DBCC Showcontig statement?
Displays fragmentation information for the data and indexes of the specified table.

99.      About SQL Command line executables

Utilities

Bcp      : console, isql , sqlagent, sqldiag, sqlmaint, sqlservr, vswitch

Dtsrun : dtswiz, isqlw, itwiz, odbccmpt, osql, rebuildm, sqlftwiz

Distrib  : logread, replmerg, snapshot

Scm

Regxmlss

100.   What is DTC?
The Microsoft Distributed Transaction Coordinator (MS DTC) is a transaction manager that allows client applications to include several different sources of data in one transaction. MS DTC coordinates committing the distributed transaction across all the servers enlisted in the transaction.

101.   What is DTS? Any drawbacks in using DTS?
Microsoft® SQL Server™ 2000 Data Transformation Services (DTS) is a set of graphical tools and programmable objects that lets you extract, transform, and consolidate data from disparate sources into single or multiple destinations.

102.   What are the different ways of moving data/databases between servers and databases in SQL Server?
There are lots of options available, you have to choose your option depending upon your requirements. Some of the options you have are: BACKUP/RESTORE, detaching and attaching databases, replication, DTS, BCP, logshipping, INSERT...SELECT, SELECT...INTO, creating INSERT scripts to generate data.

103.   How will I export database?
Through DTS - Import/Export wizard
Backup - through Complete/Differential/Transaction Log

104.   How to export database at a particular time, every week?
Backup - Schedule
DTS - Schedule
Jobs - create a new job

105.   How do you load large data to the SQL server database? bcp

106.   How do you transfer data from text file to database (other than DTS)? bcp

107.   What is OSQL and ISQL utility?
The osql utility allows you to enter Transact-SQL statements, system procedures, and script files. This utility uses ODBC to communicate with the server.
The isql utility allows you to enter Transact-SQL statements, system procedures, and script files; and uses DB-Library to communicate with Microsoft® SQL Server™ 2000.
All DB-Library applications, such as isql, work as SQL Server 6.5–level clients when connected to SQL Server 2000. They do not support some SQL Server 2000 features.
The osql utility is based on ODBC and does support all SQL Server 2000 features. Use osql to run scripts that isql cannot run.

108.       Different Authentication modes in Sql server? If a user is logged under windows authentication mode, how to find his userid?
There are Three Different authentication modes in SQLSERVER.

1. Windows Authentication Mode
2. SQL Server Authentication Mode
3. Mixed Authentication Mode

         “system_user” system function in sqlserver to fetch the logged on user name.

109.   Give the connection strings from front-end for both type logins(windows,sqlserver)?
This are specifically for sqlserver not for any other RDBMS
Data Source=MySQLServer;Initial Catalog=NORTHWIND;Integrated Security=SSPI (windows)
Data Source=MySQLServer;Initial Catalog=NORTHWIND;Uid=” ”;Pwd=” ”(sqlserver)

110.  What are three SQL keywords used to change or set someone’s permissions?
Grant, Deny and Revoke

ADMINISTRATION

111.   Different types of Backups?

o    A full database backup is a full copy of the database.

o    A transaction log backup copies only the transaction log.

o    A differential backup copies only the database pages modified after the last full database backup.

o    A file or filegroup restore allows the recovery of just the portion of a database that was on the failed disk.

112.   What are ‘jobs’ in SQL Server? How do we create one? What is tasks?
Using SQL Server Agent jobs, you can automate administrative tasks and run them on a recurring basis.
 

113.   What is database replication? What are the different types of replication you can set up in SQL Server? How are they used? What is snapshot replication how is it different from Transactional replication?
Replication is the process of copying/moving data between databases on the same or different servers. SQL Server supports the following types of replication scenarios:

Snapshot replication : It distributes data exactly as it appears at a specific moment in time and doesn’t monitor for updates. It can be used when data changes are infrequent. It is often used for browsing data such as price lists, online catalog, or data for decision support where the current data is not required and data is used as read only.

Transactional replication: (with immediate updating subscribers, with queued updating subscribers) - With this an initial snapshot of data is applied, and whenever data modifications are made at the publisher, the individual transactions are captured and propagated to the subscribers.

Merge replication: It is the process of distributing the data between publisher and subscriber, it allows the publisher and subscriber to update the data while connected or disconnected, and then merging the updates between the sites when they are connected.

114.   How can u look at what are the process running on SQL server? How can you kill a process in SQL server?

o Expand a server group, and then expand a server.

o Expand Management, and then expand Current Activity.

o Click Process Info. The current server activity is displayed in the details pane.

         In the details pane, right-click a Process ID, and then click Kill Process.

114.  What is RAID and what are different types of RAID configurations?
RAID stands for Redundant Array of Inexpensive Disks, used to provide fault tolerance to database servers. There are six RAID levels 0 through 5 offering different levels of performance, fault tolerance.

115.   How to determine the service pack currently installed on SQL Server?
The global variable @@Version stores the build number of the sqlservr.exe, which is used to determine the service pack installed.
eg: Microsoft SQL Server 2000 - 8.00.760 (Intel X86) Dec 17 2002 14:22:05 Copyright (c) 1988-2003 Microsoft Corporation Enterprise Edition on Windows NT 5.0 (Build 2195: Service Pack 3)

116.   What is the STUFF Function and how does it differ from the REPLACE function?
STUFF - Deletes a specified length of characters and inserts another set of characters at a specified starting point.
SELECT STUFF('abcdef', 2, 3, 'ijklmn')
GO
Here is the result set:
---------
aijklmnef

         REPLACE - Replaces all occurrences of the second given string expression in the first string expression with a third expression.
SELECT REPLACE('abcdefghicde','cde','xxx')
GO
Here is the result set:
------------
abxxxfghixxx

117.   What is the purpose of UPDATE STATISTICS?
Updates information about the distribution of key values for one or more statistics groups (collections) in the specified table or indexed view.

118.   What is a tuple?
A tuple is an instance of data within a relational database.

119.   sp_configure commands?
Displays or changes global configuration settings for the current server.

120.  What are sequence diagrams? What you will get out of this sequence diagrams?
Sequence diagrams document the interactions between classes to achieve a result, such as a use case. Because UML is designed for object-oriented programming, these communications between classes are known as messages. The sequence diagram lists objects horizontally, and time vertically, and models these messages over time.

121.   How do we open SQL Server in single user mode?
We can accomplish this in any of the three ways given below :-

c.From Command Prompt :-
sqlservr -m

d.From Startup Options :-
Go to SQL Server Properties by right-clicking on the Server name in the Enterprise manager.
Under the 'General' tab, click on 'Startup Parameters'.
Enter a value of -m in the Parameter.

e.From Registry :-
Go to HKEY_LOCAL_MACHINE\Software\Microsoft\MSSQLServer\MSSQLServer\Parameters.
Add new string value.
Specify the 'Name' as SQLArg(n) & 'Data' as -m.
Where n is the argument number in the list of arguments.

122.   How can I convert data in a Microsoft Access table into XML format?
The following applications can help you convert Access data into XML format: Access 2002, ADO 2.5, and SQLXML. Access 2002 (part of Microsoft Office XP) enables you to query or save a table in XML format. You might be able to automate this process. ADO 2.5 and later enables you to open the data into a recordset, then persist the recordset in XML format, as the following code shows:
rs.Save "c:\rs.xml", adPersistXML
You can use linked servers to add the Access database to your SQL Server 2000 database so you can run queries from within SQL Server to retrieve data. Then, through HTTP, you can use the SQLXML technology to extract the Access data in the XML format you want.

123.   @@IDENTITY ?

Ans: Returns the last-inserted identity value.